package lab02.test28;

import java.util.Scanner;

/**
 * Created by 123 on 2017/12/29.
 */
public class Test28 {
    public static void main(String[] args) {
        final double PI = 3.1415926;
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入一个为double类型圆的半径)");
        try {
            double radius = sc.nextDouble();
            System.out.println("圆面积:" + PI * radius * radius);
        } catch (Exception e) {
            System.out.println("输入有误，请重新输入");
        }
    }

}
